We will "accelerate the application of biomedical technology" (cf. NIBIB mission) by extending the collocated virtual reality and haptic techniques pioneered by us in our simulation of a common form of brain surgery, ventriculostomy, to a new simulator for a common step of spinal surgery, pedicle screw placement. We will help "improve health" by evaluating the spine surgery simulator for its realism and its effectiveness in teaching. The following applied research, fundamental research and evaluation tasks are proposed: Applied Research: 1. Create a three-dimensional model of the lumbar spine based on real patient CT data. 2. Produce a simulation of haptic force feedback to the surgeon's hand upon the insertion of a probe or similar instrument through human tissue or bone of different mechanical properties. 3. Simulate real-time bone volume removal or compression in probing of a screw hole. Couple accurate haptic force feedback with an after-the-fact shaded cylindrical hole model using a vertex shader. 4. Model the torque feedback from the screw hole tapping and manual screw insertion using a six degree of freedom (DOF) haptic robot (previous applications involved only a 3 DOF robot). 5. Create realistic 3D haptic and visual representations of the surgical spinal exposures in open surgery and mini-open surgery. Limit operating space through the tube retractor in the mini-open approach. Fundamental Research: 6. Surface Deformation Model. Develop a new model for the deformability of skin over the spine and apply it to the insertion of pedicle screws through the skin in minimally invasive surgery. 7. Volumetric modeling. Investigate a new method for the direct conversion of MRI data into 3D anatomical models that does not require the manual segmentation of CT scans. 8. Volume removal. Simulate real-time volume removal of bone during cutting or drilling operations. Evaluation Tasks: 9. Simulator. Grade students on simulator and judge its effectiveness by student improvement. PUBLIC HEALTH RELEVANCE: We will "accelerate the application of biomedical technology" by extending the collocated virtual reality and haptic techniques pioneered by us in our simulation of a common form of brain surgery, ventriculostomy, to a new simulator for a common step of spinal surgery, pedicle screw placement. We will help 'improve health" by evaluating the spine surgery simulator for its realism and its effectiveness in teaching.